From 0d6526f82c3cdefcca47f73f5fc08dc6f335eac6 Mon Sep 17 00:00:00 2001 From: Tim Chen Date: Mon, 21 Sep 2026 17:37:22 -0700 Subject: sched/cache: Keep nr_pref_llc_running in the runnable domain, to fix LLC mis-scheduling bug alb_break_llc() decides whether to break LLC preference during active load balance. It does so by testing that every runnable fair task on the source rq prefers its LLC: env->src_rq->nr_pref_llc_running == env->src_rq->cfs.h_nr_runnable But the two counters cover different sets. nr_pref_llc_running is updated in account_llc_enqueue()/account_llc_dequeue(), next to cfs_rq->nr_queued, so it follows queued tasks. h_nr_runnable is updated in set_delayed()/ clear_delayed() and drops delay-dequeued tasks. So under DELAY_DEQUEUE, a preferring task that goes to sleep stays counted in nr_pref_llc_running while h_nr_runnable falls. The equality then breaks, alb_break_llc() returns false, and active balance is free to pull a task off its preferred LLC. Active balance only moves runnable tasks, and this is the only LLC check it consults: once the stopper runs, LBF_ACTIVE_LB skips the per-task test in can_migrate_task(). The runnable set is the one we want. Fix it on the counter side. A task should be counted in nr_pref_llc_running exactly while it is both queued on its preferred LLC (pref_llc_queued) and runnable (!sched_delayed). Define that membership once in task_pref_llc_runnable(), and adjust the counter only through pref_llc_running_inc()/pref_llc_running_dec() from the four sites that change either input: account_llc_enqueue(), account_llc_dequeue(), set_delayed() and clear_delayed(). Gating every update on the same predicate keeps the delay, wake and dequeue paths from double-counting or underflowing; see the comments at those sites for the ordering. nr_llc_running and sd->llc_counts are not touched and stay on queued semantics. Fixes: 714059f79ff0 ("sched/cache: Handle moving single tasks to/from their preferred LLC") Closes: https://lore.kernel.org/lkml/20260827135000.735138-1-zhanxusheng@xiaomi.com/ Reported-by: Zhan Xusheng Suggested-by: Chen Yu Signed-off-by: Tim Chen Signed-off-by: Peter Zijlstra (Intel) Signed-off-by: Ingo Molnar Reviewed-by: Kayra Cizmeci Cc: # v7.2.x Link: https://patch.msgid.link/06af61afedac32e6477f57feb4d658f6c411c3af.1790035273.git.tim.c.chen@linux.intel.com --- drivers/input/misc/twl4030-pwrbutton.c | 163 +++++++++++++++++++++++++++++++++ 1 file changed, 163 insertions(+) create mode 100644 drivers/input/misc/twl4030-pwrbutton.c (limited to 'drivers/input/misc/twl4030-pwrbutton.c') diff --git a/drivers/input/misc/twl4030-pwrbutton.c b/drivers/input/misc/twl4030-pwrbutton.c new file mode 100644 index 000000000..3e94a5995 --- /dev/null +++ b/drivers/input/misc/twl4030-pwrbutton.c @@ -0,0 +1,163 @@ +/* + * TWL4030 Power Button Input Driver + * + * Copyright (C) 2008-2009 Nokia Corporation + * + * Written by Peter De Schrijver + * Several fixes by Felipe Balbi + * + * This file is subject to the terms and conditions of the GNU General + * Public License. See the file "COPYING" in the main directory of this + * archive for more details. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software + * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA + */ + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#define PWR_PWRON_IRQ BIT(0) + +struct twl_pwrbutton_chipdata { + u8 status_reg; + bool need_manual_irq; +}; + +static const struct twl_pwrbutton_chipdata twl4030_chipdata = { + .status_reg = 0xf, + .need_manual_irq = false, +}; + +static const struct twl_pwrbutton_chipdata twl6030_chipdata = { + .status_reg = 0x2, + .need_manual_irq = true, +}; + +static irqreturn_t powerbutton_irq(int irq, void *_pwr) +{ + struct input_dev *pwr = _pwr; + const struct twl_pwrbutton_chipdata *pdata = dev_get_drvdata(pwr->dev.parent); + int err; + u8 value; + + err = twl_i2c_read_u8(TWL_MODULE_PM_MASTER, &value, pdata->status_reg); + if (!err) { + pm_wakeup_event(pwr->dev.parent, 0); + input_report_key(pwr, KEY_POWER, value & PWR_PWRON_IRQ); + input_sync(pwr); + } else { + dev_err(pwr->dev.parent, "twl4030: i2c error %d while reading" + " TWL4030 PM_MASTER STS_HW_CONDITIONS register\n", err); + } + + return IRQ_HANDLED; +} + +static int twl4030_pwrbutton_probe(struct platform_device *pdev) +{ + const struct twl_pwrbutton_chipdata *pdata; + struct input_dev *pwr; + int irq = platform_get_irq(pdev, 0); + int err; + + pdata = device_get_match_data(&pdev->dev); + if (!pdata) + return -EINVAL; + + platform_set_drvdata(pdev, (void *)pdata); + + pwr = devm_input_allocate_device(&pdev->dev); + if (!pwr) { + dev_err(&pdev->dev, "Can't allocate power button\n"); + return -ENOMEM; + } + + input_set_capability(pwr, EV_KEY, KEY_POWER); + pwr->name = "twl4030_pwrbutton"; + pwr->phys = "twl4030_pwrbutton/input0"; + pwr->dev.parent = &pdev->dev; + + err = devm_request_threaded_irq(&pdev->dev, irq, NULL, powerbutton_irq, + IRQF_TRIGGER_FALLING | IRQF_TRIGGER_RISING | + IRQF_ONESHOT, + "twl4030_pwrbutton", pwr); + if (err < 0) { + dev_err(&pdev->dev, "Can't get IRQ for pwrbutton: %d\n", err); + return err; + } + + err = input_register_device(pwr); + if (err) { + dev_err(&pdev->dev, "Can't register power button: %d\n", err); + return err; + } + + if (pdata->need_manual_irq) { + err = twl6030_interrupt_unmask(0x01, REG_INT_MSK_LINE_A); + if (err) + return err; + + err = twl6030_interrupt_unmask(0x01, REG_INT_MSK_STS_A); + if (err) + return err; + } + + device_init_wakeup(&pdev->dev, true); + + return 0; +} + +static void twl4030_pwrbutton_remove(struct platform_device *pdev) +{ + const struct twl_pwrbutton_chipdata *pdata = platform_get_drvdata(pdev); + + if (pdata->need_manual_irq) { + twl6030_interrupt_mask(0x01, REG_INT_MSK_LINE_A); + twl6030_interrupt_mask(0x01, REG_INT_MSK_STS_A); + } +} + +static const struct of_device_id twl4030_pwrbutton_dt_match_table[] = { + { + .compatible = "ti,twl4030-pwrbutton", + .data = &twl4030_chipdata, + }, + { + .compatible = "ti,twl6030-pwrbutton", + .data = &twl6030_chipdata, + }, + { } +}; +MODULE_DEVICE_TABLE(of, twl4030_pwrbutton_dt_match_table); + +static struct platform_driver twl4030_pwrbutton_driver = { + .probe = twl4030_pwrbutton_probe, + .remove = twl4030_pwrbutton_remove, + .driver = { + .name = "twl4030_pwrbutton", + .of_match_table = twl4030_pwrbutton_dt_match_table, + }, +}; +module_platform_driver(twl4030_pwrbutton_driver); + +MODULE_ALIAS("platform:twl4030_pwrbutton"); +MODULE_DESCRIPTION("Triton2 Power Button"); +MODULE_LICENSE("GPL"); +MODULE_AUTHOR("Peter De Schrijver "); +MODULE_AUTHOR("Felipe Balbi "); + -- cgit v1.3.1